Mobile crane and tow truck



Feb., ll, 1969 c. R. slr-:GEL 3,426,917

4 MOBILE CRANE AND TOWVTRUCK Filed Deo. 2, 1966 Sheet of 6 Feb. l1, 1969c. R. slEGr-:L

MOBILE CRANE AND TOW TRUCK Filed Dec. 2. 1966 Feb. l1,A 1969 vc. R.SIEGEL MOBILE CRANE AND TOW TRUCK snee-t Filed Deo. 2. 1966 Feb. 11,1969 c. R. SIEGEL.

MOBlLE CRANE AND TOW TRUCK Filed D60. 2, 1966 Feb. 11, 1969 c. R.SIEGEI.

MOBILE CRANE AND TOW TRUCK Sheet Filed Deo. 2. 1966 um :Nw NN Wm, mm,

6 of G Sheet c. R. sn-:GEL

MOBILE CRANE AND TOW TRUCK Feb.. 11, 1969 med nec. 2, 196e gig UnitedStates Patent O Claims ABSTRACT 0F THE DISCLOSURE A crane mounted on atruck so that it can be employed to tow disabled vehicles as Well as tolift them and other loads completely off the ground. The boom is formedof telescopic sections that are extended and retracted by a pulley andcable system. The boom sections ride on rollers relative to each otherto facilitate their telescoping movement. The boom is supported forpivotal movement in a vertical plane by a rotatable column, Which isrotated about its axis by a pair of piston and cylinder mechanismsthrough a chain drive for positioning the Iboom. Winches are provided toextend and retract the Iboom and pivot it in a vertical plane as Well asto raise and lower the load. These Winches are mounted to rotate lwiththe column. The upstanding column is supported at its bottom and at itstop for the sake of rigidity.

Summary of the invention Tow trucks for towing disabled vehicles arefrequently equipped With a crane for lifting one end of a disabledvehicle While it is being towed. Since such cranes are mounted on arelatively small truck that can be conveniently driven on the highwaysand urban streets it has been accepted that the conventional crane on atow truck has extremely limited maneuverability. The conventional towtruck crane is just adequate to lift one end of a disabled vehicle fortowing purposes and very little more Without sacrificing a substantialamount of speed and maneuverability in the vehicle on Which the crane ismounted.

It is therefore a general object of the present invention to provide animproved crane assembly.

Another object of the present invention is to provide an improved craneassembly for mounting on a vehicle to render it mobile.

Another object is to provide an improved crane assembly that isextremely maneuvera-ble and versatile but Which can be mounted on arelatively small vehicle.

Another object is to provide an improved mechanism for telescoping acrane to facilitate its extension and retraction and to increase itsrange.

Another object is to provide a mobile crane that is relatively light inWeight and extremely maneuverable and has an extended range Withoutsacrificing lifting capacity.

Another object is to provide a mobile crane that is especially Welladapted to tow and lift disabled vehicles completely off the ground.

A further object is to provide an improved mobile crane and tow truckassembly of simple and inexpensive but sturdy construction which is veryehcient in operation.

According to this invention the improved mobile crane and tow truckassembly comprises a frame that supports a rotary base or turntablehaving an upstanding column that rotates With the base. In order toincrease its rigidity, braces extend upwardly from the frame to becoupled to the top of the column to resist the binding forces that areapplied to the column during the operation of the crane.

The boom extends outwardly from the rotary base and ICC is pivotal in avertical plane relative to the base. Accordingly, the boom Will rotatebodily in an orbit with the rotation of the base and Will also pivotvertically relative to the base.

The boom comprises a plurality of telescoping sections of latticeconstruction Which provides strength with minimum weight. The severalsections are supported on rollers that ride on way surfaces of adjoiningsections for telescopic movement relative to each other so that there isa minimum amount of resistance to their telescoping movement. A uniquepulley and cable drive is provided for telescoping the boom sections tofurther facilitate its operation.

The column supports a pair of power operated Winches. One of the Winchesoperates the cable for raising and lowering the boom in its verticalpivotal movement. The other winch forms the load hoist for drawing inand paying out the cable which is provided for connecting the load tothe crane. A pair of drums are likewise rotatably supported by therotary base for receiving the ca-ble of the pulley and cable drive fortelescoping the boom sections.

The power drive for rotating the base to position the boom comprises asprocket mounted on the underside of the base With its axis coincidingWith the axis of rotation of the base. A drive chain is in meshingengagement With the sprocket. An end of the chain is connected to onepiston and cylinder mechanism while the other end of the chain isconnected to a second piston and cylinder mechanism. Hydraulic uid isadmitted and exhausted from opposite sides of the respective piston andcylinder mechanisms to move their associated pistons for actuating thechain in its path of travel to effect rotation of the base forselectively positioning the boom.

The foregoing and other objects of this invention Which Will become morefully apparent from the following detailed description of an embodimentthereof may be achieved by the apparatus herein described by Way ofexample in connection with the illustration of its structural componentsin the accompanying drawings, in which:

Description of drawing FIGURE 1 is a side elevational View of a mobilecrane and tow truck incorporating the features of the present invention;

FIGURE 2 is an enlarged side elevational view of the crane that is shownmounted on the truck in FIGURE l, with the boom of the crane ybeingshown in its retracted condition;

FIGURE 3 is a side elevational View of the crane that is shown mountedon the truck in FIGURE l, with the boom of the crane being shown in itsextended condition;

FIGURE 4 is a front elevational view of the column portion of the craneshown in FIGURE 3;

FIGURE 5 is a detail plan view illustrating the drive mechanism forrotating the column shown in FIGURE 4;

FIGURE 6 is a plan view of the crane assembly illustrated in FIGURE 2;

FIGURE 7 is a side elevational view of the telescoping boom portion ofthe crane, showing the arrangement of the rollers that support the boomsections for sliding movement relative to each other;

FIGURE 8 is a plan view of the telescoping boom portion of the crane inits retracted condition showing the pulley and cable mechanism forextending and retracting the boom;

FIGURE 9 is a view of the boom substantially in vertical section takenalong the plane represented by Ithe line 9--9 in FIGURE 8;

FIGURE is a view of the boom substantially in vertical section takenalong the plane represented by the line 10-10 in FIGURE 8; and

FIGURE 11 is a perspective schematic view of the boom portion of thecrane illustrating the operation of the pulley and cable mechanism forexending and retracting the telescoping boom.

Description of the preferred embodiment Reference is now made moreparticularly `to the drawings and specifically to FIGURE 1 thereof whichillustrates a mobile crane and tow truck incorporating the features ofthe present invention. The mobility is provided by a conventional truckgenerally identified by the reference numeral 20. The truck includes theusual truck frame 21 on which is mounted the base of the crane, the basebeing generally identified by the reference numeral 22. An upstandingcolumn 25 is mounted on top of the base 22 and an extensible boomgenerally identilied by the reference numeral extends outwardly of thecolumn 25.

The crane base 22 includes four depending piston and cylinder mechanisms31 with one piston and cylinder mechanism 31 being located at eachcorner of the base 22. A piston rod 32 extends downwardly from thebottom end of each of the piston and cylinder mechanisms 31 and isprovided with a foot 33 at its extending end for selective engagementwith the ground. Thus, in FIG. 1, the feet 33 of the several piston andcylinder mechanisms 31 are shown retracted so that the entire unit issupported by wheels 34 of the truck 20. When it is desired to operatethe crane in a work operation, a more solid footing is desired so theconnecting rods 32 and their associated feet 33 are extended from thepiston and cylinder mechanism 31 as illustrated by the broken lines inFIG. 1 to engage the surface upon which the truck 20 is standing. Theconnecting rods 32 may be extended slightly further than i1- lusrtatedin FIG. 1 to actually lift the rear wheels 34 of the truck 20 from thesupporting surface so that a solid fixed support is provided for theoperation of the crane.

As best shown in FIGS. 4 and 6, the base 22 includes a pair of endmembers 35 that are separated from each other by a pair of parallelstructural members 36 which are of box cross section as shown in FIG. 4.The ends of the parallel members 36 are secured to the end members 35 toform a frame and a plate 37 is mounted on top of the two structuralmembers 36.

The plate 37 serves as a support for the column 25 in the manner bestillustrated in FIG. 4. An annular bearing retainer 40 is rigidly securedto the top surface of the plate 37 for receiving a tapered rollerbearing 41. A post 42 is journalled in the bearing 41 and extendsthrough an opening in the plate 37.

The upper portion of the post 42 above the plate 37 supports a member 44on which is mounted a plate 45 which is shaped into the configuration ofa sector as clearly illustrated in FIG. 6. Depending skirts 46 aresecured to the rectilinear edges of the plate and a boom foot 47 extendsforwardly and upwardly of the depending skirts 46 for supporting theboom 30. The plate 45 and its supporting structure constitutes aturntable which carries the column 25 to render it rotatable.

The plate 45 is attached to the member 44 by bolts 48 as illustrated inFIG. 4. A frame of the column 25 is mounted on the plate 45 andcomprises a pair of upstanding parallel plates 50 that have their bottomends secured to the plate 45 by welding or the like. The plates 50 areconnected to each other at their uppermost ends by a plate 51. A bearing52 is mounted on top of the plate 51 for cooperation with a bearing 53which is journalled thereon as shown in FIG. 2. The bearing 53 includestwo pairs of ears 54 extending radially therefrom. Each pair of ears 54is spaced sufficiently to receive a flattened end 55 of one of a pair ofbraces 56. A pin 57 extends through each pair of ears 54 and itsassociated flattened end 55 of the brace 56 for connecting thecooperating brace 56 to the bearing 53.

The opposite end of each of the two braces 56 is likewise provided witha flattened end 58 disposed between a pair of ears 59 that are rigidlysecured to the end plate 35 as clearly illustrated in FIG. 6. A pin 60extends through each pair of ears 59 and their associated ilattened end58 as shown in FIGURE 2 for securing the bottom end of the two braces 56to the end member 35 of the crane base 22. With this arrangement, thecolumn 25 is journalled for rotation in the tapered roller bearings 41at its lower end while the upper end is journalled in the bearing 53`that is supported by the two braces 56 for rigidly supporting thecolumn 25 in a vertical position. The upper support of the column 25 bythe braces 56 produces a great deal of strength in the column 25 forsupporting the loads lifted by the crane, and yet the structural membersneed not be extremely heavy for carrying the stresses that aredeveloped.

Partial `rotation of column 25 is achieved by means of a hydraulicallyactuated chain drive which is best illustrated in FIGURE 5. It comprisesa pair of piston and cylinder mechanisms 64 and 65 mounted underneaththe plate 37 A piston rod l66 extends outwardly of the piston andcylinder mechanism '64 and is connected to a drive chain 67 which is inmeshing engagement with a sprocket 70 that is secured to the bottom endof the post 42 as depicted in FIGURE 4. The opposite end of the chain 67is connected to a piston rod 71 that extends outwardly of the piston andcylinder mechanism 65. In order to effect rotation of the sprocket 70 tothereby produce a corresponding rotation of the column 25, hydraulic uidis admitted to opposite ends of the cylinders of the piston and cylindermechanisms 64 and 65. Thus, if it were desired to effect rotation of thesprocket 70 in a clockwise direct-ion, as viewed in FIGURE 5, hydraulicpressure would be admitted into the port 72 of the piston and cylindermechanism 64 and exhausted through the port 73. At the same time,hydraulic pressure would be admitted into the port 74 of the piston andcylinder mechanism 65 and exhausted through the port 75. A suitablehydraulic control valve (not Shown) is provided for simultaneouslyregulating the tiow of hydraulic pressure into and out of the piston andcylinder mechanisms 64 and 65.

The boom 30 is formed of `four telescoping sections 80, 81, 82 and 83which are of lattice construction to give maximum strength for a givenweight. The section is the largest section of the boom and the section81 slides into the interior of the section 80. In similar manner, thesection 81 is larger than the section 82 and the latter slides into theinterior of the section 81. The smallest section of the boom 30 is thesection 83 which is adapted to slide into the interior of the section82. In this manner the four sections of the boom 30 telescope relativeto each other for the purpose of extending and retracting the boom.

'Ihe boom 3e is supported by the boom foot 47 for pivotal movementrelative to the column 25. To this end, a pair of stub shafts 85 and 86extend through suitable openings in the boom yfoot 47 as well as throughsuitable opening-s in a pair of plates 89 and 90` that are rigidlyattached to the bottom end of the boom section 80 as clearly shown inFIGURE 6. The stub shaft 85 is also supported Aby a plate 91 that isattached to the forward portion of the plate 45 and a pulley 92 isrotatably supported by the stub shaft 85 between the plates '89 and 91.A-s illustrated in FIGURE 4, a pair of pins 93 retain the shaft 85 inthe assembly. One pin 93 is inserted diametrically into one end of theshaft 85 outside of the plate 91 and the other pin 93 is likewiseinserted diametrically into the opposite end ofthe stub shaft 85 outsideof the bracket 47. The stub shaft 86, in addition to being supported bythe boom foot 47 is also supported by a plate 94 and a pair of pins 95to retain the assembly on the Stub shaft 86. One of the pins 95 isinserted transversely in the stub Ishaft 86 outside of the boom foot 47while the other pin 95 is inserted in a like manner in the opposite endof the stub shaft 86 outside of the plate 94 as clearly shown in FIGURE4.

The boom sections are supported `for sliding movement relative to eachother by a unique Isystem of rollers that ride on ways `formed onadjacent hoorn sections to facilitate the extension and retraction ofthe boom 30. The arrangement of the rollers is best illustrated in FIGS.7 and 10 which depict two different vie-ws of the several boom sections.The boom section 80 is, of course, xed against longitudinal movement sothat it Iis stationary during the extension and retraction of the Ihoorn30. The section 81 is the next largest section and it moves into and outof the interior of the stationary section 80. It is supported for suchsliding movement into and out of the stationary section 80 by a pair ofrollers 101 that are rotatably secured to the bottom end of the sect-ion81 by suitable brackets 102. One of the rollers 101 is illustrated inFIGURE 7 while both of them are illustrated in the cross sectional viewof vFIGURE l0. The two brackets 102 are secured to the movable section81 at its lowermost end and each of the rollers 101 is rotatably carriedby one of these brackets 102. The rollers 101 are so positioned thattheir periphery rolls along the way surfaces formed on the interior ofthe stationary section 80. The periphery of the rollers 101 are actually-in contact with the way surfaces provided by the interior of a pair ofangles 103 which are a part of the stationary section 80 and constitutetwo corners of this section as clearly shown in FIG- URE 10. The upperend of the movable section 81 is guided by a pair of rollers 106 thatare respectively rotatably supported by a pair of brackets '107 that aresecured to the stationary section 80 as illustrated in FIGS. 2 and 3.Only one of the rollers 106 is illustrated in FIG- URE 7 but anothersuch roller is disposed on the other side of the section 80. The tworollers 106 are journalled in their cooperating brackets 107 and arelocated so that their peripheries rest upon a way surface formed on theexterior upper surface of the section 81 to guide the latter section inits longitudinal movement into and out of the stationary section 80.

Similar roller arrangements are provided for guiding and facilitatingthe movement of the two sections 82 and 83. Thus, the section 82 isprovided with a pair of brackets 109 disposed on either side of itsbottom end with each bracket 109 rotatably supporting a roller 110.Accordingly, the rollers 110 move with the section 82 and they arelocated so that their peripheries engage the interior surface of thesection 81. To this end, the two rollers 110 ride along `respective way1surfaces formed along the interior surfaces of angles 111 whichconstitute the lower two longitudinal corners of the movable section 82.

The upper end of the movable section 82 is guided by a pair of rollers115, one of which is illustrated in FIGURE 7, although an identicalroller is disposed on the opposite side of the top end of the section82. The two rollers 115 are rotatably supported by two respectivebrackets 116 that are shown in FIGS. 2, 3 and 7. The brackets 116 arefixed to the boom section 81 for movement therewith but the rollers 115are located se that their peripheries engage way surfaces formed on theupper exterior surface of the movable boom section 82. Therefore, as theboom y82 moves into and out of its cooperating movable section 81, thelower end of the section 82 is guided by the rollers 110 which move withit in its longitudinal movement and .roll along the way surfaces formedon the interior surface of the section 81, and the upper end of thesection 82 is guided by the rollers 115 which roll and engage the waysurfaces formed on the section 82 but do not otherwise move with thelongitudinal movement of the section 82 since their axes are mounted forAmovement with the adjacent larger section 81.

The same roller arrangement is provide for the last movable boom section83. A pair of brackets 119 are secured for movement with the boomsection 83 as clearly shown in FIGURE l0 and each of the brackets 119rotatably supports a roller 120. The rollers 120 are located so thattheir peripheries ride along the interior surfaces of the adjacent boomsection 82. Thus, the peripheries of the rollers 120 ride along waysurfaces formed by the interior surfaces of respective angles 121 whichactually form the lower longitudinal corners of the movable boom section82. Accordingly, the lower end of the boom section 83 is supported forsliding movement by the two rollers 120 riding along the way surfacesformed within the interior of the section 82 by the angles 121. Theupper end of the boom section 83 is guided by a pair of lrollers 122that are journalled in brackets 123. Only one roller 122 and one bracket123 are shown in FIGURE 7 but another identical roller 122 and anotherbracket 123 are located on the opposite side of the upper surface of theboom section 83. The brackets 123 are mounted on the adjacent boomsection 82 but the rollers 122 are located so that their peripheriesengage way surfaces formed along the adjacent movable boom section 83.Thus they serve to guide the boom section 83 for movement relative tothe adjacent section 82 as the section 83 moves into and out of thesection 82 during the retraction and extension of the boom 30.

A novel reave or pulley and cable arrangement is provided for eifectingthe extension and retraction of the boom 30. The pulley and cablearrangement is of simple and relatively inexpensive construction and yetoperates extremely efficiently while requiring a very minimum ofmaintenance. The system is best illustrated in the schematic View ofFIGURE l1 and comprises a continuous cable 130, one end of which isattached to a drum 131 and the other end is attached to a drum 132 whichare illustrated in FIGURE 6. The two drums 131 and 132 are rotated inunison, in the same direction, so that both ends of the cable are eitherbeing taken in and wound about the two drums 131 and 132 respectivelyfor extending the boom 30 or they are being simultaneously paid out forretracting the boom 30. The two drums 131 and 132 are supported abovethe plate 45 by a pair of brackets 133, one of which is illustrated inFIGURE 2. The drum 131 is located on one side of a transmission 1-34while the other drum 132 is coaxial with the drum 131 but is located onthe opposite side of the transmission 134. The transmission 134 includestwo drive shafts connected to rotate the drums 131 and 132simultaneously. The transmission 134 is actuated by a motor 135 that hasa sprocket keyed to its output shaft for actuating a drive chain 136that is also in meshing engagement with a sprocket on the input shaft ofthe transmission 134. Energization of the motor 135 in either directionwill therefore actuate the transmission 134 in a like direction toeffect rotation of the two drums 131 and 132 for extending andretracting the boom 30.

The cable extends from the two drums 131 and 132 into the interior ofthe several sections of the boom 30 for operating engagement with aplurality of pulleys that are rotatably mounted within the several boomsections for cooperation with the cable. As most clearly illustrated inFIGURE lil, the cable 130 passes from the drum 131 along the undersideof the rotatable pulley 92 for guiding the cable into the interior ofthe stationary boom section 80. In like manner, the cable 130 passesfrom the drum 132 to the underside of a pulley 137 which is rotatblysupported by the stub shaft 86. The pulley 137 also serves to guide thecable 130 to the interior of the boom section 80. From the pulley 92 thecable 130 passes to a pulley 140 which is rotatably supported at theupper end of the stationary boom section 80. On the other side of theboom section 80, the

cable 130 passes from the pulley 137 to a pulley 141 which is 'likewiserotatably supported by the stationary boom section 80 at its uppermostend with the axis of the pulley 141 being in substantial alignment withthe axis of the pulley 140. The moutning of the pulleys 140 and 141 onthe boom section 80 is also illustrated in FIG. 9 where the pulley 140is journalled on a shaft 142 which is carried by a side plate of theboom section 80. In like manner, the pulley 141 is journalled on a shaft143 that is carried by the opposite side plate of the boom section 80.

The cable 130 passes underneath and over the pulley 140 and extendsrearwardly therefrom to an angularly disposed pulley 148 that isrotatably supported at the bottom end of the movable boom section 81. Inlike manner, on the other side of the boom structure the cable 130passes underneath the pulley 141 and over it to extend rearwardly forengagement with an angularly disposed pulley 149 that is rotatablycarried at the bottom end of the section 81 opposite the side thatcarries the pulley 148. IIt should be especially noted that the pulleys140 and 141 are supported at the upper end of the section 80 while theangularly disposed pulleys 148 and 149 are rotatably supported at thebottom end of the movable section y81. The mounting of the angularlydisposed pulley,148 and 149 is clearly shown in FIGURE l0 where thepulley 148 is shown as journalled on a stub shaft 150 that is carried bya bracket 151 which is mounted on a side plate of the movable boomsection 81. The pulley 149 is carried on the opposite side of thesection 81, being journalled on a stub shaft 152 which is carried by abracket 153 that is supported by a side plate of the boom section 81.

From the angularly disposed pulley 148, the cable 130 passes upwardly toa pulley 160 which is rotatably supported by the upper end of the boomsection 81. In like manner, the cable 130 passes upwardly from theangularly disposed pulley 149 to a pulley 161 which is also rotatablysupported at the upper end of the section 81 with its axis in alignmentwith the axis of the pulley 160. The pulley 160 is located on one sideof the upper end of the section 81 While the pulley 161 is disposed onthe opposite side. It should be noted that the angularly disposedpulleys 148 and 149 are both supported at the bottom end of the movablesection 81 while the pulleys 160 and 161 are rotatably supported at theupper end of this same section 81. The mounting of the pulleys 160 and161 on the section 81 is clearly illustrated in FIG. 9. As there shown,the pulley 160 is journalled on a stub shaft 162 that is carried by aside plate of the section 81. In like manner, the pulley 161 isjournalled on a stub shaft 163 that is carried on the opposite side ofthe boom section 81.

As best shown in FIGURE l1, the cable 130 passes under and over thepulley 160 to extend rearwardly for engagement with an angularlydisposed pulley 168 that is rotatably supported by the movable boomsection 82. In like manner the other portion of the cable 130 passesunder and over the pulley 161 to extend rearwardly into operatingengagement with an angularly disposed pulley 169 which is also rotatablysupported at the bottom end of the boom section 82. It should be againnoted that the parallel pulleys 160 and 161 are supported -by the boomsection 81 while the two angularly disposed pulleys 168 and 169 aresupported by the succeeding boom section 82. As a result, the spacing ofthe pair of pulleys 160 and 161 from the pair of pulleys 168 and 169 mayvary.

The mounting of the angularly disposed pulleys 168 and 169 is best Shownin FIGURE l0. The pulleys 168 is journalled on a stub shaft 170 that iscarried by a bracket 171 which is supported by a side plate of the-movable boom section 82. The opposite side plate of the boom section 82supports a bracket 172 which carries a stub shaft 173 upon which thepulley 169 is journalled.

The cable 130 extends from the angularly disposed pulley 168 to a pulley180 which is rotatably supported at the upper end of the same section82. In the same manner, the cable extends upwardly from the angularlydisposed pulley 169 to a pulley 181 which is also rotatably supported atthe upper end of the section 82 on the side opposite the side thatsupports the pulley 180. The axes of the two pulleys 180 and 181 are inalignment so that the pulleys are parallel to each other. It should beagain noted that the angularly disposed pulleys 168 and 169 are locatedat the bottom end of the section 82 while the two parallel pulleys 180and 181 are located at the upper end of the same section 82. Themounting of the pulleys 180 and 181 on the boom section 82 is clearlyshown in FIGURE 9. The pulley 180 is journalled on a stub shaft 182 thatis carried by a side plate of the boom section 82. Similarly, the pulley181 is journalled on a stub shaft 183 which is carried on the side ofthe section 82 that is opposite the side that carries the stub shaft182.

The continuous cable 130 passes underneath and over the two pulleys 180and 181 into engagement with a pulley 185 that is rotatably supported atthe bottom end but on the top surface of the inal movable boom section83. As illustrated in FIGURE 10, the pulley 185 is journalled on a stubshaft 186 which is carried by the top plate of the movable boom section83. It should be again noted that the two parallel pulleys 180 and 181are rotatably supported by the upper end of the boom section 82 whilethe pulley 185 is rotatably supported at the bottom end of the adjacentboom section 83. As a result, the spacing of the pulleys 180 and 181from the pulley 185 may vary. The pulley 185 is provided for greaterflexibility and eliiciency in the operation of the pulley and cablesystem although the system would also function if the cable wereanchored at the bottom of the movable boom section 83 instead of beingwound around the pulley 185.

The operation of the pulley `and cable system for extending andretracting the boom 30 may be best understood from the schematic view inFIGURE 1l. The boom 30 is illustrated in that ligure in its extendedcondition with the several -movable boom sections 81, 82 and 83extending a maximum amount outwardly of the sect1on from-which theytelescope. As a result, each pair of angular pulleys is spaced a minimumamount from its adjacent cooperating pair of parallel pulleys. Thus, thetwo parallel pulleys and 141 are spaced a minimum amount from theircooperating angular pulleys 148 and 149. In like manner, the parallelpulleys and 161 are spaced a minimum amount from their immediatelycooperating angular pulleys 168 and 169. The parallel pulleys and 181 ofthe movable section 82 are likewise spaced a minimum amount from thesingle pulley that is located on top of the final section 83. Thepulleys and their cooperating movable sections are in the position shownbecause the cable has been taken up by the two drums 131 and 132 so thata minimum amount of cable is within the interior of the boom 30. Suchtaking up of the cable on the drums 131 and 132 has caused the abovementioned pairs of pulleys to be drawn toward each other for extendingthe several boom sections relative to each other.

If the drums 131 and 132 are rotated to let out more cable into theinterior of the boom 30, the relaxing of the cable will cause theseveral sections to telescope into each other by gravity. Thus, as thecable 130 is wound off of the drums 131 and 132, the relaxing of thecable will cause the boom section 81 to move into the stationary section80 and such movement of the section 81 will cause the two angularlydisposed pulleys 148 and 149 which are mounted on the section 81 to movewith it to increase their spacing from the two parallel pulleys 140 and141, which, as previously mentioned, are rotatably suppported by thestationary section 80. Since the pair of angular pulleys 148 and 149 aremoving away 9 from the pair of parallel pulleys 140 and 141, the excesscable let off of the drums 131 and 132 is utilized for the increasedspacing between the two pairs of pulleys.

When the boom section 81 arrives at its limit of downward movement bygravity, the section 82 will begin telescoping into the section 81 andthereby move its associated pair of angularly disposed pulleys 168 and169 `with it to increase their spacing from the pair of parallel pulleys160 and 161. The additional cable will therefore be required toaccommodate this latter spacing between the two pair of pulleys.

When the movable boom section 82 reaches its downward limit of movementwithin the interior of its cooperating section 81, additional relaxationof the cable 130 by the rotation of the two drums 131 and 132 will causethe final movable boom section S3 to move downwardly by gravity into itsadjacent cooperating section 82. As the section 83 moves downwardly intothe section 82, the pulley 185 moves with the section `83 to increaseits spacing from the pair of parallel pulleys 180 and 181. Theadditional cable that is provided by the rotation of the drums 131 and132 is utilized to accommodate the increased spacing between the pulley185 and the pair of parallel pulleys 180` and 181. In this manner theboom 30 is retracted selectively by regulating the rotation of the drums131 and 132 to let out the desired amount of cable to accommodate theextent of boom retraction that is required.

The downward telescopic movement of the several sections is limited by aplurality of stops 235, 236 and 237 during the retraction of the boom30. As depicted in FIGURE 7, the stops are engaged by the lower supportrollers 101, 110 and 120` of the respective sections. Thus a pair ofstops 101 are located at the lower end of the stationary section 80 tobe engaged by the pair of rollers 101 that are supported by the adjacentcooperating boom section 81. As the movable section 81 retracts into thestationary section r80, the rollers 101 move with it until they engagethe pair of stops 235 to terminate further retracting movement of thesection y81 relative to the section 80. In like manner the stops 236 aremounted at the lower end of the movable boom section 81 to be engaged bythe two rollers 110 that are supported by the movable section 82. Whenthe latter is retracted into the section 81 its associated rollers 110engage the stops 236 to prevent lfurther retracting movement of thesection `82. The stops 237 are fixed to the lower portion of boomsection 82 to be engaged by the rollers 120 which are carried by themovable section 83- `for limiting the retracting movement of the movableboom section 83. Although one of each of the stops 23S, 236 and 237 isshown, it should be understood that another one of each of these stopsis mounted on the other side of the same boom section for cooperationwith the guide roller that is likewise mounted on the other side of theadjacent boom section.

The extension of the boom sections relative to each other is likewiselimited. This can be accomplished by suitable stops but in theillustrated embodiment the limitations are imposed by the pulley andcable system itself by reason of the fact that the parallel pulleys arein the path of travel of the angular pulleys so that the movements ofthe latter are stopped before the boom sections become extended to anextent which would unduly weaken their carrying capacity.

When it is ldesired to extend the boom 30, the drums 131 and 132 arerotated in the opposite direction to take up the cable 130 onto thedrums 131 and 132 so that less cable is Idisposed Within the interior ofthe boom 30. As the cable 130 is taken up, it can no longer accommodatethe increased spacing of the several pairs of pulleys in the mannerdescribed above. As a result, the taking up of the cable on the drums130 and 131 will cause the pair of angular pulleys 148 and 149 to bemoved closer to their associated pair of parallel pulleys 140 and 141.Since the angularly disposed pulleys 148 and 149 are mounted on the-bottom end of the movable boom section l81 and the parallel pulleys 140and 141 are carried at the upper end of the stationary section 80, thesection 81 will move with the angularly disposed pulleys 148 and 149 toprogressively be extended out of its associated boom section 80. Inidentical manner, the continued taking up of the cable onto the drums131 and 132 will produce a telescoping extension of the boom sections 82and 83 out of their cooperating boom sections. In this manner the boom30 is readily extended or retracted by the operation of the two drums131 and 132 for paying out and taking up the cable 130.

The novel pulley and cable system for extending and retracting the boom30 in combination with the unique roller arrangement that supports theboom sections for their telescopic movement produces a very eicientlyoperating boom. It has been -found that the retraction and extension ofthe boom can be effected while the boom is carrying a very heavy load togreatly increase the versatility of the crane.

The pivotal movement of the boom 30 in a vertical plane about the axisof the shafts 85 and `86 is effected by a winch generally identified bythe reference numeral and illustrated in FIGURE 4. The winch 190comprises a spool 191 that is rotatably supported between the two plates50 of the column 25. A hydraulic motor 192 is mounted on one of theplates 50 as shown in FIGURE 4 and is connected to actuate atransmission 193 which, in turn, is connected to rotate the spool 191 ineither direction of rotation for taking up or letting out a cable whichis shown in FIGS. 2, 3 and 6i. With one end of the pulley being attachedto the spool 191, the opposite end of the pulley is xed to a bracket 196that is mounted on the column 25 as clearly illustrated in FIGURE 2. Thecable between the bracket 196 and the spool 191 is wound about a seriesof pulleys for obtaining a mechanical advantage to increase the capacityof the motor 192 for lifting the boom 30 in its pivotal movement and theload attached thereto. The cable and pulley system is secured to theupper end of the boom 30 by a bracket 201 to which an arm 202 ispivotally connected and extends rearwardly therefrom with the oppositeend of the arm 202 carrying a pair of parallel pulleys 203 and 204having their axes in alignment and in a horizontal plane as best shownin FIGURE 6. Another transverse pulley 205 is carried at the end of thearm 202 with its axis in a Vertical plane. These three pulleys cooperatewith a pair of pulleys 206 and 207 that are journalled in a bracket 208which is pivotally connected to another bracket 209 that extendsupwardly from the top of the column 25. The cable 195 is wound aboutthese tive pulleys in well known 'manner for obtaining a mechanicaladvantage to facilitate raising and lowering the boom 30 in its pivotalmovement in a vertical plane about the two shafts 85 and 86.

Another winch generally identified by the reference numeral 215 iscarried by the column 25 for actuating a cable 216 to raise and lowerthe load that is being carried by the crane. The winch 215 comprises aspool 217 which has one end of the cable 216 attached to it and isrotatably supported between the two plates 50 of the column 25 so thatit may be rotated to take in and let out cable 216 for raising andlowering the load that is being carried by the apparatus. The spool 217is rotated by a hydraulic motor 217 which is connected to actuate atransmission 218 that is, in turn, connected to the spool 217 forrotating the latter in either direction of rotation to let out or takein the cable 216.

The cable 216 extends from the winch 215 upwardly along the boom 30 overa pulley 220 that is rotatably supported on a stub shaft 221 carried bythe bracket 201 as illustrated in FIGURE 6. As shown in FIGURES 2 and 7,the bracket 201 rotatably supports another pulley Z22 that is disposedon the underside of the top of the final section 83 beneath the pulley220. The cable 216 passes over the pulley 222 as well as the pulley 220and is provided with a hook 22S at its extending end for attachment tothe load that is to be lifted or towed. A chain extension 226 with ahook 227 is illustrated in FIGURE 2 with the boom 30 being shown in itsretracted position and the hook 227 being connected to an idler arm 230for securing the cable 216 and its chain extension 226 when the unit isbeing moved without a load.

The boom is shown in its retracted position in FIGURE 2 in a pivotableposition in which the hook 225 may be readily attached to a vehicle fortowing the latter along a desired path of travel. On the other hand, theboom 30 may be extended several times the length illustrated in FIGURE 2and may be pivoted upwardly in a vertical plane a substantial amount sothat loads attached to the hook 225 may be raised relatively greatdistances and moved about as desired. Thus, the apparatus of the presentinvention may be operated as a crane with a heavy capacity and extensiverange for lifting and moving loads about and yet the boom 30 may beretracted to a short length as to enable the apparatus to be efficientlyemployed for the purpose of towing other vehicles.

From the foregoing detailed description of the present invention, itwill be readily understood that an improved mobile crane and tow truckhas been provided in which the telescopic movement of the boom sectionshas been facilitated by the utilization of rollers for guiding andsupporting the boom sections in their telescopic movement relative toeach other and the sections are actuated in their telescopic movement byan improved pulley and cable system which cooperates with the rollersupports for increasing the capacity, range and maneuverability of theboom. The maneuverability is further increased by extending the boomfrom rigidly supported rotary column which extends upwardly from theframe to carry the power operated actuating mechanisms as well as theboom. The column is rotated by a unique hydraulically actuated chaindrive for swinging the boom in a horizontal direction.

Although the illustrative embodiment of the invention has been describedin considerable detail for the purpose of disclosing a practicaloperative structure whereby theinvention may be practisedadvantageously, it is to be understood that the particular apparatusdescribed is intended to be illustrative only and that the novelcharacteristics of the invention may be incorporated in other structuralforms without departing from the spirit and scope of the invention asdefined in the subjoined claims.

The principles of the invention having now been fully explained inconnection with the foregoing description of the illustrativeembodiment, the invention is hereby claimed as follows.

I claim:

1. In a crane; `a frame; a plurality of telescoping sections forming aboom for the crane with one of said sections being secured at a pivot tosaid frame to constitute a fixed section; a plurality of operatingpulleys rotatably supported by each of said sections; a pair of guidepulleys rotatably supported at said pivot by said frame; a cable inengagement with said guide pulleys for guiding the cable into said fixedsection so that said cable is parallel to said boom when it enters thefixed section to avoid placing any unnecessary lateral loads on saidboom, said cable extending from said guide pulleys into operatingengagement with said operating pulleys; and means for drawing in andreleasing said cable selectively to extend and retract said boomsections.

2. A crane according to claim 1 wherein said boom is pivotable about anaxis which is also the axis of rotation of said guide pulleys so thatsaid cable will enter the boom along a line that is parallel to the boomfor all angular positions of said boom.

3. A crane according to claim 1 wherein said telescoping sectionscomprise a bottom fixed section having a top portion and a bottomportion with the bottom portion being coupled to said frame; asucceeding upper intermediate section in telescoping engagement withsaid fixed section to form the portion of the boom above said fixedsection with said intermediate section having a top portion and bottomportion; and an uppermost section at the top of said boom in telescopingengagement with said intermediate section; and said pulleys comprise apair of top pulleys at the top portion of said fixed section; a pair oftop pulleys at the top portion of said intermediate section; a pair of-bottom pulleys at the bottom portion of said intermediate section; andcoupling means at the bottom of said uppermost section, the two portionsof said cable extending from said winding means being engaged with thepair of pulleys at the top of said fixed section and thence intoengagement with said pair of bottom pulleys at the bottom of saidintermediate section, the two portions of said cable extending upwardlytherefrom into engagement with said pair of top pulleys of saidintermediate section and thence downwardly to said coupling means forcoupling said cable to the bottom portion of said uppermost boomsection; whereby the drawing of said cable causes said pair of bottompulleys on said intermediate section to be shifted toward said pair oftop pulleys of said fixed section for extending said intermediatesection outwardly of said fixed section, and said coupling means isshifted toward said pair of top pulleys of said intermediate section forextending said uppermost section outwardly of said intermediate section,and when said cable is released by said drum means said boom sectionsretract by gravity and said pairs of pulleys separate from each otherand from said coupling means.

4. A crane according to claim 1 wherein said telescoping sectionscomprise said bottom fixed section having a top portion and bottomportion with the bottom portion being coupled to said frame; asucceeding upper intermediate section in telescoping engagement withsaid fixed section to form the portion of the boom above said xedsection with said intermediate section having a top portion and a bottomportion; an uppermost section at the top of said boom in telescopingengagement with said intermediate section; a longitudinal way strip onsaid bottom fixed section presenting a flat way surface; a rollerattached to the bottom of said intermediate section and presenting afiat peripheral surface in position to ride along the flat way surfaceof said longitudinal way strip for supporting said intermediate strip inits telescopic movement; a pair of longitudinal way strips formed witheach way strip presenting a fiat way surface on said intermediatesection; a second roller mounted at the top of said bottom sectionpreventing a fiat peripheral surface in position to ride along the flatway surface of the first of said way strips on said intermediate sectionfor guiding and supporting said intermediate section in its telescopicmovement; a roller attached to the bottom of said uppermost section andpresenting a flat peripheral surface in position to ride along the flatway surface of the second Way strip of said intermediate section forsupporting said intermediate section in its telescopic movement; asingle flat way surface on said uppermost section; and a roller carriedat the top of said intermediate section and presenting a fiat peripheralsurface in position to ride along said single fiat way surface of saiduppermost section to guide and support said uppermost section in itstelescopic movement.

5. A crane according to claim 4 including a plurality of stops mountedon said telescopic sections for engagement by said rollers to limit thetelescoping movement of said sections relative to each other.

(References on following page) 13 14 References Cited 1,345,304 6/ 1920Zied 212-55 UNITED FOX et al. 916,317 3/ 1909 Hood@ 212-59 ANDRES H.NIELSEN, Primary Examiner. 1,345,304 6/1920 Zied 212-55 5 2,833,4225/1958 Ferwerda et al. 212--55 U.S. C1. X.R.

3,029,954 4/1962 Grant 212-55 212-144

